How statement and proof provenance work
The first chip identifies the source of the statement or construction; the second identifies the source of its local proof or verification.
- Literature-sourced: the exact statement appears in a cited source; only wording and notation differ.
- AI-adapted: a semantically identical restatement of literature-sourced material, modulo indexing, notation, and boundary cases adopted by the library.
- AI-generated: a genuinely novel statement formulated by AI, with no source for the claim itself.
These labels describe origin, not correctness: citations and verification chips remain separate evidence.
has exactly six elements, is non-abelian, and its elements have orders , and
Example
Let , the three-element set of natural numbers , , , and let be its symmetric group (The symmetric group : the bijections of a set under composition), a group under composition ( is a group under composition, and it is non-abelian whenever has at least three distinct elements). Then:
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has exactly six elements, namely
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is not abelian: while ;
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the orders of its elements are , for each of the three transpositions, and for each of the two -cycles.
Facts & Assumptions
Given: and with the operation , , and identity (The symmetric group : the bijections of a set under composition).
, and are pairwise distinct natural numbers: and , so , and , while no natural number is a member of itself (The natural numbers (von Neumann), Every natural number is a transitive set and is not a member of itself); so has exactly three elements.
is a group under composition; the cycle symbols and denote the permutations described in The symmetric group : the bijections of a set under composition ( is a group under composition, and it is non-abelian whenever has at least three distinct elements, Group and abelian group).
Two functions are equal exactly when they agree at every point; a function on is determined by the triple , and is a bijection of exactly when those three values are pairwise distinct, since three distinct values in a three-element set exhaust it (Injection, surjection, bijection).
Finiteness and counting: means a bijection exists, and is then the unique such natural (Finite, countably infinite, countable, uncountable, Equinumerous sets, and , The order of a finite group and the order of an element, with when no positive power of is the identity).
If then for , and conversely a with and for is the order (The order of a finite group and the order of an element, with when no positive power of is the identity, If then iff is an integer multiple of , the powers are distinct, and has exactly elements; if has infinite order then only for ).
Verification
Writing each element of as the triple of its values at , the six listed permutations are , , , , and . These six triples are pairwise different, so the six permutations are pairwise different.
Each transposition satisfies , since it exchanges two points and fixes the third, so applying it twice returns every point to itself; and , since it moves two points.
, since and is the least natural that is .
Every element of is one of the six. Let ; its triple has pairwise distinct entries by [L3]. There are three possible values for ; for each, two remaining values for ; and then is forced to be the one element of left over. Running through those six combinations produces exactly the six triples listed in step 1.1.
Composites, computed pointwise. sends , , , giving the triple , which is . And sends , , , giving , which is .
Let , so sends . Then sends , , , which is the triple , that is ; and sends , , , so it is .
Each transposition has : by step 1.2, while , so is the least with .
By steps 1.1 and 2.1 the set consists of exactly the six listed elements, so the map sending to respectively is a bijection; hence and . This is claim 1.
By step 2.2 the two composites differ, since the triples and differ at ; so is not abelian, which is claim 2.
Each of and has order : by step 2.3, , and , so ; and with and , so as well.
Claims 1, 2 and 3 are steps 3.1, 3.2 and steps 1.3, 2.4 and 3.3 taken together; the orders occurring are exactly , and .
Remarks
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This is the first explicitly non-abelian group in the library. Claim 2 instantiates the general statement of is a group under composition, and it is non-abelian whenever has at least three distinct elements at the three distinct points ; the pair of transpositions used there is the pair used here.
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No element of has order , by claim 3, so by If then iff is an integer multiple of , the powers are distinct, and has exactly elements; if has infinite order then only for every cyclic subgroup has at most three elements and none of them is all of : the group is not cyclic. That also follows from claim 2, every cyclic group being abelian (, and every cyclic group is abelian).
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The elements , , here are the natural numbers of The natural numbers (von Neumann), hence sets; nothing in the computation uses anything about them beyond their being three distinct objects.
Depends on
- The symmetric group $\operatorname{Sym}(X)$: the bijections of a set $X$ under composition
- $\operatorname{Sym}(X)$ is a group under composition, and it is non-abelian whenever $X$ has at least three distinct elements
- Group and abelian group
- Powers $g^{n}$: natural exponents in a monoid and integer exponents in a group, with $g^{0} = e$
- Exponent laws in a group: $g^{m+n} = g^{m}g^{n}$ and $(g^{m})^{n} = g^{mn}$ for all $m, n \in \mathbb{Z}$, and $(gh)^{n} = g^{n}h^{n}$ **when $g$ and $h$ commute**
- The order $|G|$ of a finite group and the order $\operatorname{ord}(g)$ of an element, with $\operatorname{ord}(g) = \infty$ when no positive power of $g$ is the identity
- If $\operatorname{ord}(g) = n$ then $g^{k} = e$ iff $k$ is an integer multiple of $n$, the powers $g^{0}, \dots, g^{n-1}$ are distinct, and $\langle g \rangle$ has exactly $n$ elements; if $g$ has infinite order then $g^{j} = g^{k}$ only for $j = k$
- Finite, countably infinite, countable, uncountable
- Equinumerous sets, $A \approx B$ and $A \preceq B$
- Injection, surjection, bijection
- The natural numbers $\mathbb{N}$ (von Neumann)
- Every natural number is a transitive set and is not a member of itself
Used by
Nothing in the library uses this result yet.
Dependency tree · next 3 levels
Direct dependencies and their dependencies through the next three levels: 78 results over 26 levels. An arrow runs from a result to what uses it, and this result sits at the bottom with a heavier outline. Click the chart to enlarge it.
Sources
- Symmetric group (Wikipedia) (standard reference, not scraped)
- Dihedral group of order 6 (Wikipedia) (standard reference, not scraped)